Purification of oil soluble sulphonate



Mata sat. 10,1940 7 2,214,037

UNITED STATES PATENT OFFICE Francis M. Archibald, Elizabeth, N. J.,assignor to Standard Oil Development Company, a corporation ofDelawareNo Drawing. Application January 29, 1938,

Serial No. 187,657

10 Claims. (011260-504) This invention relates to improvements in orderto make it possible to emulsiiy the oil purifying oil solublesulphonates obtained from compound in water.

the treatment of petroleum oils with. sulphuric The acidtreatment of alubricating oil or a acid and to products obtained thereby. petroleummedicinal white oil is carried out by I The oil soluble sulphonates areby-products applying the acid in stages, that is, agitating the 6 fromthe sulphuric acid treatments of lubricating oil with a relatively smallamount of sulphuric oils or petroleum medicinal white oils. They areacid compared to the whole amount that is to be also known as mahoganysulphbnates or-mahog used, for a short period of time, discontinuin anysoaps. In commercial production the most the agitation and allowing themixture to settle,

1 desirable mahogany soaps are obtained as byduring which period asludge drops out as a lower products in the manufacture of petroleummediclayer and is withdrawn before more sulphuric inal white oils. Thisis due to the fact that the acid is added and the mixture agitated. Theacid treats in the manufacture of white oils are concentration of oilsoluble sulphonic acids in the relatively heavy when compared'with theacid oil increases during the first few stages of the 1 treats used inthe manufacture of lubricating sulphuric acid treatment until it reachesamaxi- 1 oils and consequently the soaps produced thereby mum value,after which stage additional sulare of better quality and better yieldsof the oil phuric acid treatments do not produce more oil solublesulphonates are obtained forthe quantisoluble i sulphonic acids. Whenthis stage is ties of material handled. The oil soluble sulreached, theoil is neutralized and the oil soluble o phonates are first formed asoil soluble sulphonic sulphonic acids are removed in the form of a acidsand are found dissolved in the acid oil layer soap. after the acidsludge separates out at the end According to this invention, the acidoil is of the sulphuric acid treatments of mineral lubrineutralized withan alkaline salt of a weak acid, eating oil fractions. Traces of oilsoluble sulsuch assoda ash, sodium carbonate, or potassium g5 phonicacids are also found occluded in the carbonate. An excess of alkali isused to aid separated acid sludges. No efforts are made to in preventingemulsification while extracting the recover them and the sludges aregenerally disoil soluble sulphonate soap from the oil. The posed of aswaste products. The acid oils also soda ash is added, dissolved in asmall amount 1 contain sulphur dioxide, some unsettled acid of water.Thepresence of free caustic is avoided. 3o sludge particles and tracesof free sulphonic acid At the same time, an alcohol is added as asolvent in addition to the oil soluble sulphonic acids. The to dissolveout the oil soluble sulphonate. Methyl, 'oil soluble sulphonic acids aregenerally neutralethyl, isopropyl or other aliphatic alcohols conizedwith alkalies before attempting to finish the taining not over 4 carbonatoms to the molecule white oils, as the oils in the acid condition aremay be used, though the use of isopropyl alcohol very corrosive anddiflicult to handle. The neuis preferred. The concentration of theisopropyl 35 tralization of the oil soluble sulphonic acids yieldsalcohol that is added is about 55% or suificient the oil solublesulphonate soaps and at the same 'so that upon mixing with the watersolution of time the neutralization of sulphur dioxide and soda ash, itwill form an isopropyl alcohol soluthe free sulphuric acid results inyields of intion of about. 50% concentration. S uflicient al- 40 organicsalts which are recovered in a mixture cohol is added to obtain an oilsoluble sulphonate 40 with the oil soluble soaps. soap solution of notover 8%. By using an alcohol An object of this invention is to separateth of this concentration, only a minimum amount of oil solublesulphonates from the inorganic salts. oil will be extracted with the oilsoluble 'sul- This purification is desirable where the oil solublephonates. The separated alcohol solution of the sulphonatesoaps are tobe used for emulsifying soap is then concentrated by evaporating oil 5purposes, since the presence of the inorganic substantially all of thealcohol andpart of the salts partially or completely destroys the powerwater until the salt layer formed-by this evaporaof the oil solublesulphonate soaps to emulsify tion has 'a gravity of about 12 B., due tothe oil in water, this effect being-dependent on the solution of sodiumcarbonate, sodium sulphate,

concentration of inorganic salts present. The and sodium sulphite. Theoil soluble'sulphonate 50 presence of small amounts of salt-makes itnecessoaps are partly thrown out of solution in the sary to add a largeamount of soap to oil in order form of curds. The hot solution ofinorganic to make it emulsifiable in water, and a larger salts andsoapwvith part of the soap thrown out amount of salt makes it necessaryto add accesof solution is then allowed to settle and the faquesoryemulsifiers, such as sodium resinate, in ous salt layer separated. Theseparated aqueous 55 solution containing the oil soluble sulphonatesoaps partly in solution and partly in suspension in the form of curdsis then mixed with isopropyl alcohol of 80 to 90% concentration. Thesolution obtained in this way must not contain over about 10 to 14% ofsoap and the final concentration of the alcohol is to be kept between 65and 80%. This mixture is thoroughly agitated at about 60 C. in order todissolve all of the soap. The solution is then allowed to settle for a'period of 1 to 7 days, during which time a concentrated aqueous saltsolution settles out and is withdrawn. The pH of the purified soapsolution is maintained below 9.5 according to this process. This iscarefully controlled and the solution must not indicate alkalinity whena phenolphthalein indicator is used. Too much water in the solution,insufiicient settling or too high a temperature of settling prevents theprecipitation of the salt solution containing the alkali and under theseconditions the pH will be found to be above 9.5. The separated upperlayer of alcoholic soap solution is then withdrawn and the alcohol andwater present evaporated and oil is added to increase the fluidity ofthe soap.

The invention is not to be limited to the specific embodiments shown orthe specific examples given, nor to any theories advanced as to theoperation of the invention, but in the appended claims it is intended toclaim all inherent novelty in the invention as broadly as the prior artpermits.

I claim:

l. The process of obtaining purified oil so1uble sulphonates frompetroleum oils comprising neutralizing an oil that had been treated withconcentrated sulphuric acid with an alkaline.

salt of carbonic, acid, extracting theneutralized oil with a 55% aqueoussolution of an aliphatic alcohol containing not more than 4 c rbon atomsin the molecule, separating the aqueous alcoholic layer solutioncontaining not over 8% of the oil soluble sulphonates, evaporating theaqueous alcoholic solution until an aqueous salt layer is formed havinga gravity of about 12 B., separating the upper layer and adding theretoa monohydric aliphatic alcohol containing not over 4 carbon atoms in themolecule to obtain an alcohol solution of a concentration between 655 to80% and containing not over 14%of oil soluble sulphonates dissolvedtherein, allowing the mixture'tosettle until the pH of the alcohol layeris below'9.5, separating the upper layer containing the purified soapsand recovering same by evaporating the water and alcohol from theseparated alcohol layerto obtain a concentrated oil soluble sulphonate.

2. The process of obtaining purified oil soluble sulphonates frompetroleum oils comprising neutralizing an oil that had been treated withfuming sulphuric acid with an alkaline salt of carbonic acid, extractingthe neutralized oil with a 55% aqueous solution of an alcohol containingnot more than 4 carbon atoms in the molecule, separating the aqueousalcoholic layer solution containing not over 8% of the oil solublesulphonates, evaporating the aqueous alcoholic solution until an aqueoussalt layer is formed having a gravity of about 12 B., separating theupper layer and adding thereto a monohydric nates dissolved therein,allowing the mixture to settle until the pH of the alcohol layer isbelow 9.5, separating the upper layer containing the purified soaps andrecovering same by evaporating the water and alcohol from the separatedalcohol layer to obtain a concentrated oil soluble sulphonate.

3. The'process of obtaining purified oil soluble sulphonates frompetroleum oils comprising treating the oil with sulphuricacid,separatingthe sludge formed thereby,- neutralizing the acid oilwith a salt of carbonic acid and an alkali metal of the class consistingof potassium and sodium. extracting the sulphonate compounds with anaqueous monohydric aliphatic alcohol containing, not over 4 carbon atomsto the molecule in a concentration of about 50%, evaporating the extractto obtain an aqueous salt layer having a gravity of about 12 B. allowingthe solution to settle, separating the precipitated salts, mix-- ing theresidual solution with said monohydric aliphatic alcohol to obtain afinal concentration of the alcohol of 65 to and a solution containingnot over 10 to 14% of the oil soluble sulphonates, allowing the mixtureto settle until the said alcoholic layer is no longer alkaline tophenolphthalein, separating the upper layer containing the purifiedsoaps and recovering same by evaporating the residual solution whileadding oil to separate the alcohol.

4. The process of obtaining purified oil soluble sulphonates frompetroleum oil comprising treating the oil with sulphuric acid,neutralizing with an aqueous solution of sodium carbonate, adding anaqueous olution of isopropyl alcohol of about 55% concentration,separating the alcohol layer, evaporating the alcohol layer until anaqueous solution of about 12 B. gravity is formed, allowing the mixtureto settle, separating the upper layer and adding thereto suificientisopropyl alcohol to obtain a solution containing not over 10 to 14% ofoil soluble sulphonates in an ispropyl alcohol solution of 65 to 80%concentration, allowing the mixture to settle, separating the upperlayer containing the purified soaps and recovering same by evaporatingthe alcohol layer while adding oil to obtain a purified oil solublesulphonate.

5.- Process according to claim 4 in which temperatures of about 60 C.are used while diluting the concentrated solution of oil solublesulphonate and temperatures of below 40 C. are used during settling.

6. Process according to claim 4 in which isopropyl alcohol of about tois added to dilute the concentrated soap solution.

7.- The process of obtaining purified oil soluble sulphonates whichcomprises neutralizing a petroleum oil that had been treated withconcentrated sulphuric acid with an alkaline salt of carbonic acid,extracting the neutralized oil with a 55% aqueous solution of an alcoholcontaining not more than 4 carbon atoms in the molecule, separating thealcohol layer containing about 8% of oil soluble sulphonates,evaporating the aqueous "alcoholic solution to form an aqueous saltlayer of about 12 B. gravity, separating the upper layer and addingthereto monohydric aliphatic alcohol containing not over 4 carbon atomsin the molecule to obtain an aqueous alcoholic solution of aconcentration between 65 to 80% and containing not over 14% of oilsoluble sulphonates dissolved therein, allowing the mixture to settleuntil the alcoholic layer is no longer alkaline when using phenol- 752,214,087 'phthalein as an indicator, separating two aqueous salt layersand evaporating water and alcohol from the separated alcohol layer.

8. The process of obtaining oil soluble s phonatesaccording to claim 7in which an oil is added as the alcohol and water are evaporated fromthe separated alcohol layer.

9. The process of obtaining purified oil soluble sulphonates accordingto claim "iv in which the alcohol layer is separated after the pH valueis reduced below 9.5. 10. The process of obtaining purified oil solu-"ble sulphonates from petroleum oils comprising neutralizing an oil thathad been treated with concentrated sulphuric acid with an alkaline saltof carbonic acid, extracting the neutralized oil with an aqueoussolution of not over 55% concentration of an alcohol containing not morethan 4 carbon atoms in the molecule, separating the aqueous alcoholiclayer solution containing not over 8% of the oil soluble sulphonates,evaporating the aqueous alcoholic solution until an aqueous salt layeris formed having a gravity of about 12 B., separating the upper layerand adding thereto a monohydric-aliphatic alcohol containing not over 4carbon atoms in the molecule to obtain an alcohol solution of aconcentration between 65 to 80% and containing not obtain a concentratedoil soluble sulphonate.

FRANCIS M ARCHIBALD.

